News Rights

Peril at the Pump

Ethanol-based fuels are not only harmful to motorcycle engines and the environment, they are often purposely mislabeled to keep consumers in the dark

March 21, 2022

By Kali Kotoski

Photos: Jeff Kardas

Life is full of choices, but even at the gas station there can be bad ones if you’re not an informed motorcyclist.

For carbureted motorcycles and bikes manufactured before 2001, ethanol-laced gasoline can have negative effects on the motorcycle’s fuel system without proper maintenance and storage. But it can lead to costly mishaps for more modern fuel-injected motorcycles, too.

The big problem is that ethanol-laced gasoline is virtually everywhere, as it’s found in 98 percent of the country, according to the U.S. Department of Energy. Typically blended in at 10 percent ethanol, or E10, virtually every octane rating contains ethanol unless it is clearly marked as NO ETHANOL ADDED or ETHANOL FREE or NON-ETHANOL.

The labeling of ethanol-boosted and regular gas varies from state to state and supplier to supplier, making it even more confusing for the average citizen. Many would say that’s deliberately so, especially when talking about its polyonymous juiced-up cousin E15/Unleaded 88/88 Octane, which contains 15 percent ethanol and is illegal to be used in motorcycles, boat engines, lawnmowers and chainsaws, to name a few.

Derived from corn primarily from the nation’s heartland, ethanol-blended gasoline first gained prominence as an octane booster during fuel shortages during World War II and, later, the 1970s oil crisis. But E10 wasn’t enshrined into the energy mix until the mid-2000s with the Energy and Policy Act of 2005, which established the Renewable Fuel Standard and, later, the Energy and Independence and Security Act of 2007. In 2009 E15 was approved to be sold only in winter months, and as of 2020 is available in 30 states at 2,300 fueling stations, according to federal data.

The impetus for blending ethanol into gasoline is primarily two-fold: shore up America’s energy independence and security following 9/11, and limit greenhouse-gas emissions. Today, the nearly $20 billion ethanol industry is a political dogfight, with politicians opposed claiming it contributes to a loss of taxes due to generous incentives, while proponents say it has lowered prices at the pump. Meanwhile, environmentalists hate it and even the U.S. Environmental Protection Agency concluded in 2019 report that it is making the air dirtier.

Luckily, a 2019 EPA waiver to aid struggling farmers and allow E15 to be sold year-round — which the AMA fought against — was struck down by the courts, but only after the market was flooded with the stuff. The AMA argued that E15 could lead to misfuelling, void motorcycle warranties and cause engine failure and overheating, concerns that the EPA recognized as valid.

While E15 is a whole can of worms politically and economically, and can be directly harmful to motorcycle engines, E10 still may damage motorcycles according to Chris Real, owner of DPS Technical, Inc.

Real pointed out that fueling up with E10 isn’t a catastrophe for newer, fuel-injected motorcycles, but the danger for motorcycles burning any form of ethanol boils down to water.

“The ethanol fuels are pretty good absorbers of water and that is where our root problem lies,” Real told American Motorcyclist. “The corrosive effect that water has leaves the components open to degradation and deposits, which are especially bad for carbureted bikes.”

Because gasoline has a volumetric expansion of 15 to 20 percent when it gets hot, it brings air and humidity into the tank — which finds its way into the fuel system — when it cools.

While carburetors aren’t as common as they once were, plenty of motorcycles still use them and motorcyclists know all too well how much of a pain they are to rebuild, and how expensive it is to have them rebuilt.

But even for fuel-injected motorcycles, deposits from ethanol gasoline can have bad outcomes.

“Mainly, for fuel injection systems, the sprayer nozzles are these tiny little holes that, if clogged, can actually be very dangerous,” Real said. “Imagine you are coming off a stop light and the bike stalls because some crud blocked the nozzle.”

Besides that, fuel pumps and fuel filters can also be damaged by a buildup of deposits. To mitigate the chance of a failure here, Real advises using a fuel stabilizer additive when parking any bike, or using non-ethanol fuel (available at some stations) or even prepackaged ethanol-free chainsaw gasoline that can be found at hardware or home improvement stores. The prepackaged fuel is especially useful for vintage and carbureted bikes.

Another concern with ethanol-laced fuel is shelf life. Typically, corn gas has a shelf life of two to three months, while non-ethanol fuel is rated for six months. Besides using a fuel additive to keep the gas healthy, Real advised keeping the tank filled to limit headspace for air and humidity to get in.

Ethanol-laced fuels can also drastically reduce fuel economy because they don’t have the same amount of latent stored energy, which results in substantially less power potential per volume. But many real-world variables, such as ambient temperatures, tank temperature, engine displacement (fuel economy more drastically decreases in motorcycles under 200cc), weather conditions and, most importantly, rider behavior on the throttle and transmission shifting, factor into reduction of fuel economy. Basically, riders will NOT go as far on ethanol-laced fuels.

“Fuel economy is one of the main tradeoffs with ethanol fuel,” Real said. “We are being force-fed these fuels and we will have to contend with them.”

Basically, he explained, for consumers to safeguard their motorcycles, they need to be aware of what they fill up with at the pump, of engine gasoline requirements, and also practice good storage and maintenance habits.

“If the manufacturer says the bike is all good on E10, groovy…until you store it. Definitely don’t use E15, and for sure don’t use that E85 flex-fuel stuff because that can park you,” he said, adding that consumers should be aware that E85 is 85 percent ethanol and commonly confused with E15.

The AMA has been steadfast in its stance for proper labeling at the fuel pump to better educate and warn consumers of what they’re putting in their bikes, and the data bears out that concern. Proponents of ethanol-blended fuels who have clashed with the AMA claim that because it’s not approved for motorcycles, there is no concern.

However, marketing gimmicks increased those concerns. Sure, unless the pump says no ethanol added, consumers are guaranteed to get an E10-level corn additive. But in recent years, that juiced-up cousin E15 has been deliberately labeled as Unleaded 88 or 88 Octane (while E85 flex fuel is not clearly differentiated). Most of the time warning labels for gasoline with 15 or 85 percent ethanol are either missing, obscured, prone to falling off, or misleading. There is no reason whatsoever to label illegal and harmful E15 as “Unleaded 88” unless you’re actively trying to hide what it is from consumers.

“No consistency. No clarity. No protection for the consumer,” the National Marine Manufacturers Association has called these marketing gimmicks.

The Outdoor Power Equipment Institute has called it “disingenuous,” citing concerns of misfuelling and the need for improvements in pump labeling. A 2020 consumer study by the organization found that only 22 percent of consumers knew Unleaded 88 or 88 Octane was E15 in disguise! It also found that 64 percent of consumers assume that gas sold at the pump is safe for any engine.

So, when filling up at the pump and storing your motorcycle, here are some general rules to follow:

  • Research the recommended fuel for your bike. If it says E10 is not recommended, don’t use it if you can help it (sometimes you can’t).
  • Pay attention to the labels. If it doesn’t say ethanol-free, you are getting 10 percent corn regardless of the octane level.
  • Never use the E85 flex fuel approved for certain passenger vehicles.
  • If it says 88 anywhere and is cheaper, remember that’s really just E15 with makeup.
  • Store your bike properly. Use fuel stabilizers, empty the carb bowls if possible, and keep a full tank for carbureted bikes. Pour in pre-packaged ethanol-free fuel for fuel injected bikes.

You can join the AMA’s fight to improve labeling and have warnings prominently displayed. Subscribe to the AMA’s Action Alerts at

*This article was originally printed in the March edition of American Motorcyclist and has been updated to clarify the loss of fuel economy from ethanol-blended fuel. To read the full issue, click HERE